In modern day packaging, polyethylene film is frequently laminated to one or both sides of a paper substrate and the resulting laminated material is used for a wide variety of purposes.
One of the industries making a very substantial use of a product of this kind is the dairy industry which uses the product to make containers for milk, cream and the like. The manufacture of, for example, milk cartons from large sheets of paper laminated with polyethylene film on one or both sides is accomplished by cutting the large sheets into blanks of predetermined form and assembling them by methods which are well known in the art. The process results in the production of a substantial quantity of scrap material which is useless for recycling as a paper product since it is contaminated with polyethylene and is useless for recycling as a polyethylene product since it is contaminated with paper.
Current methods of attempting to recycle this material involve the passage of the scrap material through a device, well known in the art, known as a hydro-pulper which, in the presence of large quantities of water, either with or without other additives, causes a substantial separation of paper fibres from the polyethylene film and enables the paper fibres entrained in the water to be recovered to a substantial degree for recycling purposes. However, the polyethylene film which is a product of the hydro-pulper operation is still a virtually useless product because the separation from the paper fibres is incomplete and the polyethylene film, being contaminated by an unacceptably high level of paper fibres is useless as a recycling product.
Heretofore, it has not been possible to conveniently, economically and practically, separate the remaining paper fibres from the polyethylene film to produce a polyethylene film which is sufficiently free of paper fibre contamination to be acceptable as a usable polyethylene product.